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MAIZE; 



An Attempt at Classification 



E.^ Lewis Sturtevant, M. D., 



Director of the New York Agricultural Pxpekimkm Station. 



GENEVA, DECEMBER, 1883. 



PRINTED FOR PRIVATE DISTRIBUTION ONLY: 

Botanical friends will confer a favor by forwarding criticisms and 
suggestions to the author. 



RuCllKSIKK, N.V.: 

DEMOCRAT AND CHRONICLE PKLMT. 

1884, 



• Alas? 



MAIZE. 

AN ATTEMPT AT CLASSIFICATION. 



HISTORICAL NOTES. 

The races of Indian corn now recognized by tanners, — the pops, the flints, the softs, the sweets, 
and the dents, — seem to have been known from a distant antiquity. The pop corn can perhaps be 
identified as the sacred corn of Titiaca, for the rice pop forms the cone-shaped ears, and according 
to Rivers and Tschudi, the Peruvians worshiped ears of maize that were cone-shaped, and Squiers 
describes a variety at present in cultivation in this region as scarcely three feet high, bearing ears not 
longer than one's finger, and covered with vitreous grains. The rice pop has angular and pointed 
kernels, and Dobrezhoffer names in Paraguay a corn with these characteristics. Flint corn was found 
in cultivation by the northern Indians by the earliest visitors, and hard corn, perhaps flint, is men- 
tioned in Peru by Garcelasso de la Vega, and in Paraguay by Dobrezhofifer. Soft corn seems first to 
have been described as Tuscarora, found in cultivation by the Tuscarora Indians upon the settlement 
of North Carolina, and brought by them to their reservation in New York State, upon their removal 
thither in 1712. Sweet corn is said to have been taken to Massachusetts from the region of the 
Susquehanna upon the return of Sullivan's expedition in 1779, and this appears to have been an eight- 
rowed sweet. Another variety, probably the Evergreen, is mentioned incidentally by Bordley in i8oi_^__J 
Dent corn is vaguely described by Acosta and other early writers, but as this is one of the kinds 
which have been found in the Peruvian htiacas, its antiquity is placed beyond question. 

Among the so-called species of maize of some authors is Zca rostrata, Bon. of Peru, with 
mucronate seeds ; Z. macrocarpa, Klotz. of Peru, a soft corn ; and Z. cioagiia, Mol., of Chili, the 
seeds flinty. 

Among the varieties of corn which have been traditionally derived from the northern Indians, are 
the King Philip and Sioux flint ; the Squaw, Tuscarora and Wyandotte soft, and the sweets. 

The intermixture of the several varieties of corn was well known to the aborigines, and was 
attributed, by some of them at least, to the roots and small fibers reaching to, and communicating 
with each othe# This mixture they do not seem to have been concerned about, as very many of the 
more full descriptions of the crops of North American Indians speak of the variety of colors not only 
of ears, but of the kernels intermixed upon the ear. It hence seems all the more surprising that our 
variations not only should have been handed down to us so well defined and so perfectly retaining 
their characteristics, but that these characteristics should have been so firmly maintained under the 
careless system of cultivation pursued by the European colonists, as well as by the present American 
farmers. 

BOTANICAL RELATIONS. 

In view of the history of maize, it has always seemed to me unreasonable to class the various 
races under one botanical species, and yet with the current statements and beliefs of its constant 
intercrossings and changes, no other conclusion seemed tenable. It is therefore with satisfaction 
that I offer this paper to the public, the data being derived from a collection of 231 kinds of ear corn 
from various localities, and the growing together in the New York Experiment Station garden of 135 
different kinds of seed, from which 404 representative ears were selected. From these ears every 
kernel of divergent type has been culled, and two cross-sections made, for the purpose of study. 



If typical examples of the kernels of the various races of corn be examined, there will be found 
a difference in structure in the kernel, which may be thus described : 

Pop Corn— The split kernel exposing a chit and corneous matter, the latter being very hard. 
Upon exposing the dry kernel to a high temperature, the whole seed explodes into a white, fluffy mass, 
the interior structure being everted about the chit and epidermis. Type— New England Fop. Fig. i. 

Flint Corn— The split kernel exhibiting three structures, the chit, visible starch, and corneous 
matter enveloping. Type — Canada Flint. Fig. 2. 

Soft Corn— The chit and visible starch constituting the whole structure, no corneous matter 
being present. Type — Tuscarora. Fig. 3. 

Sweet Corn— The structure, chit and corneous matter alone, the latter translucent and more or 
less shrivelled and crumpled. Type— Evergreen Sweet. Fig. 4. 

Dent Corn— Three structures observable, the chit, starchy matter extending to the summit, and 
corneous matter upon the sides. l>pe — Minnesota Dent. Fig. 5. 




Fig. I. Fig. 2. Fig. J. Fig. 4. Fig. j. 

With our collection it becomes quite easy to discriminate a number of sub-races within each race, 
the types being more or less well defined, but indicating that there exists three sub-types at least. 
Had we been aware of the existence of these sub-types at the time of planting, our studies would 
have led to far more satisfactory results. 

FIELD OBSERVATIONS. 

Before proceeding to a description of the sub-races, we offer our observations made upon the crop 
produced by the various seeds, some selected for presumed purity to type ; others for known or pre- 
sumed hybridization ; and yet others from peculiar characters offered by their position or apparent 
divergence in structure. 

Pop Corn- — P>om pop ears : whole number of ears examined, 960, the majority pop ears, but some 
flint ears. Quite a number of sweet corn kernels were present, some few kernels of the dent structure, 
also a few obscurely of flint type, but these variations in type not all occurring in the same sub-race. 

Flint Corn — Number of ears examined, 499. From the seed presumed to be pure, all flint ears 
were produced, and no kernels of other type were found. Of flint hybridized with dent, the yield was 
flint ears and dent ears, with scarcely a mixture of either type of kernel. Of flint hybridized 
with sweet, the yield was sweet ears, flint ears and dent ears, with scattered kernels of soft, flint and 
dent type, but all not present upon the same type of ear. ^ 

Soft Corn — Number of ears examined, 176, the ears all on type, but a large number of the ker- 
nels flinty, and a very few sweet corn kernels. The Tuscarora showed no effect of hybridization 
from other types. The Squaw corn held its colors, but lost its structure in a large degree. 

Sweet Corn — 27 named varieties. Number of ears examined, 933, all the ears of sweet type, but 
flint kernels common on the 8-rowed sweet type, dent kernels on the Evergreen type of ear, and 
rarely a kernel of soft corn structure upon both types. Sweet Corn crossed by flint : 33 ears : sweet 
ears of 8-rowed type with some flint kernels, and sweet ears of Evergreen type with some dent 
Sweet kernels. Cor)i, from pop ears: 116 ears examined. The yield embraced pop, flint and 
sweet ears, some flint kernels, occasionally a dent kernel and a soft kernel. 

Dent Corn — 532 ears examined. All the ears either dent or flint, with rarely the presence of 
kernels of the soft type, and occasional kernels of the flint type on the dent ears ; some of the ears, 
however, while yet dent in structure, showing a flinty character. Flinty kernels from dent ears, 
probably not a true flint by structure : number of ears examined, 234 : the crop dent ears, flint ears 
and dent ears of a flinty character ; no admixture of other type kernels, except rarely a kernel of a 
flint type. Flint on dent ; 42 ears : the ears and kernels all dent. 



PERMANENCE OF TYPES. 

In all the races we find a great variety of color in the kernel, especially so in the soft race, where 
the color penetrates into the structure of the kernels which possess corneous matter through current 
hybridization. In the other races of corn, the red color, often passing to a black purple, is a very 
strong character, the red ears usually showing no change in color of kernel through current hybridi- 
zation. The cobs (glumes) also may be red or white, irrespective of the color of the kernel. The 
number of rows varies in all the varieties with which we are acquainted, but yet one number is 
usually the most prevalent, and from pure seed the variation' seems to be within well defined limits. 
Thus, the Waushakum, a pedigree corn of the Canada type, is nominally 8-rowed, but yet ears 
6-rowed, lO-rowed and i2-rowed are of occasional occurrence. 

The sub-races which our collection enables us to separate, are shown more clearly to the eye than 
by description. On account of the interfertilization which has taken place between the various types 
which in localities are grown together, often two or more types can be selected from one crop, but 
there seems a tendency for each type to maintain itself, so that usually the various ears can be readily 
referred to their proper types. 

THE POP SUB-RACES. 

I'op corn presents three well marked sub-races : the common pop, pearl pop and rice pop. 

Common Pop is usually eight rowed, the ears cylindrical, long, with small cob; small stalked; 
kernels rounded ; red ears rarely, if ever, occur. 

Through hybridization, apparently, it imperceptibly changes its type and its capacity to pop over 
the fire, starch becoming visible in its kernels. Its kernels may perhaps be found upon the ears of the 
pearl pop sub races, but are doubtfully recognized. They do not occur with the kernels of the rice 
pop. The kernels of the other sub-races of pop do not appear with its kernels. Sweet corn kernels 
may appear .through current hybridization. The greatest variation* in structure of kernels from cur- 
rent hybridization or otherwise, as found by us, is shown in Fig. 6. 

When flint structured corn raised from pop seed was planted, variations occurred as shown in 
Fig. 7, as taken from five ears. 







Fi 



I'iK. 7- 



Pearl Pop is many rowed, the kernels very hard and flinty, unusually deep, often triangular in 
section and with a polish that gives the name to the class. The ears taper slightly, and red ears are 
abundant. Cone-formed ears sometimes occur. There is usually a tendency to visible starch in small 
quantity in the structure ; kernels of sweet corn appear through current hybridization ; some kernels 
also which can be referred doubtfully to the flint. 

The greatest variation observed is given in Fig. 8. 



POP. M,I.\T. I'OP I1.I.VI-. I'OP. SWEEr. 

Fig. S. 

* In the illustration of variations occurring in the various races or types, that from current hybridization is figured 
well as those from the use of hybridized seed. 



Rice Pop is many rowed ; the tendency to cone-shape in the ear is very marked ; kernels imbricated 
on the cob ; the stalk is small and the kernels round strongly over the butt of the cob. Ears of the 
pearl form, however, occur. Red ears are very common. Sweet kernels occur through current 
hybridization, as also kernels which may be referred to the flint, and doubtfully to the dent type. The 
extreme variations found are given in P'ig. g. 




As offering some clue as to the permanency of types, we give in Figure lo the variations observed 
in the crop from sweet kernels taken from the common pop ear : in Fig. ii, sweet kernels from the 
pearl pop ear, and in Fig 12, sweet kernels from a rice pop ear, being used as seed. 




Fl.lNl'. SWEET. 




Fii:. 10. 






FLINT. FLINT. I'OP. .SWliKl 

Fif;. 12. 

THE FLINT SUB-RACES. 

P'lint ears show likewise three sub-races, but are not as easily described as are the 
pops, though they may be readily recognized in certain localities ; one northern, another intermediate, 
the third southern in its character. These types are frequently intermingled in a crop, but the 
tendency for each to produce its own type is well marked, and collections of most divergent ears at 



first sight can usually be refeired to their proper position. As these sub-races were not recognized at 
the time of the planting of our seed, we offer in Figure 13 the variations in the type of kernel noted 
in the ears of the flint race by which it will be seen that rarely a dent type kernel is to be found. In 
the sweets crossed upon flints, however, the sweet ears contained the soft and doubtful dent type of 
kernel figured. 






/Vs,''. /?. SWEKT CROSSED ON FL(NT. 

Canada Corn — The ear cylindrical, shortish, usually 8-rovved; the kernel rounded, stalk small, 
'I^ype — Canada \'ellow. 

New England— The ear tapering, long, usually 12-rowed, but often 8-rowed in varieties. The 
stalk large. Type — Ciolden Sioux and New England Twelve-rowed. 

Southern Hominy — The ear tapering, the kernels strongly rounding over the butt to meet the 
small stalk ; many rowed, the kernels very flinty and the corneous portion thickened at the sides and 
shallow at apex. Type — Southern Hominy. Our collection, however, contains too few ears for sat- 
isfactory determination. 

SOFT CORN SUB-RACES. 

The soft corn shows in our collection two types, but our material is not sufficient for a satis- 
factory definition. It is probable that a third type e.\ists, as kernels of this structure are occasionally 
to be found on sweet ears of the third type, as also on some dents. The variations in structure of 
kernel that were observed are noted in Figure 14. 







Fig. 14. Fig. ij. Fig. lb. 

Northern — The ear cylindrical, shortish, 8-rowed; the stalk small. Type — One ear from Red 
River of the North. 

Tuscarora — The ear tapering, long, 8 to 12-rowed, the stalk rather large. Type — Tuscarora and 
Squaw corn. The Squaw corn very subject to current hybridization from the flints. 

SWEET CORN SUB-RACES. 

Sweet corn ears present also three sub-races, but as the distinction was not recognized at the time of 
planting, our records of variation are defective. Two of these sub-races are very distinct and 
evidently do not influence each other's kernels by current hybridization. 

Early — The ears cylindrical, usually 8-rowed, the kernel but slightly crinkled; rounded, the stalk 
small. Current hybridization from flint pollen and from soft pollen. Type — Eight-rowed Sweet of 
some seedsmen. The variations observed in the kernel are shown in Figure 15. 

Medium — The ears tapering, usually 12-rowed. The kernel slightly crinkled, the stalk rather 
large ; current hybridization from flint pollen. Type — Asylum. 

Large Late — The ears tapering, many rowed ; the kernel wrinkled and wedge-shaj^ed, rounding 
strongly over the butt to rneet the small stalk. Variation by current hybridization from dent 
pollen and perhaps soft pollen. Type— Stowell's Evergreen. The variation in type of kernel is 
shown in Figure 16. 



THE DENT SUB-RACES. 

Dent corn presents three sub-races, which a little experience very readily separates 
Eight-Rowed— The ear cylindrical, usually 8-rowed; the kernel rounded and broad, creased; the 

stalk small. Type— Benton or Yankee. The variation observed was to the soft kernel type, as 

shown in Figure 17. 






/>V/7. Fig. 18. Fig. ig. 

Tennessee — The ear tapering, 12 or i4-ro\ved, rather long, the stalk above medium size ; 
the kernels polygonal, so as to form a wedge shaped sulcus between the rows. Type — Watson and 
Tennessee. Blount's Prolific is an 8 or lo-rowed variety of this type. The variations observed in 
the kernel were to the soft type, as shown in Figure 18. 

Western — The ear tapering, usually short ; at times cone-shaped or long-oval; the kernels round- 
ing strongly over the butt to meet the small stalk ; kernels wedge-shaped, thus leaving no sulcus 
between the rows. Types — Queen of the Prairie and Proctor's Bread. The variation observed is 

shown in Figure lo. 

UNCLASSED TYPES. 

We have in our collection two ears, which cannot be classed with the other races, and which I 

•therefore provisionally term Intermedia tk. One is a variety called Cuban, and grown in South 

Florida ; the ear cone-shaped, the kernel rounding over the butt to meet the small stalk, the kernels 

excessively flinty, the corneous matter wanting at the summit, but strongly developed at the sides. 

The other, the Japanese Striped Maize, the kernel, however, less flinty than in the Cuban. 

THE RACES GROUPED. 

We will now group our races and sub-races, as herein established, in an illustrated table. 

Sub-Race A. Suh-Race B. Sub-Race C. 





i;i;ni;in w.kv. 



.lAPANKSF, Bl'KII'KI 



Fis:. 20. 




GENERALIZATIONS. 

A critical examination of the 3733 ears of our crop in their relations to the seed planted, and the 
opportunities for interfertilization, would seem to sufficiently justify the following general conclusions : 

Cross-fertilization of the current year is manifested on the kernel, and not on the ear, and, as has 
been sufficiently noted, this influence is not reciprocally strong as between the races, or even the sub- 
races, and the resistance to current hybridization is more strongly marked in some races, sub-races or 
varieties than in others. 

Hybridization in the seed used produces a variety of ears, but each ear in general is quite close to 
one of the parent types ; an intermixture of kernel in no case seems to be produced. Reciprocal 
fertilization between two races does not seem to be productive of equal effect. 

An inference gathered from observation rather than founded upon recorded data leads me to believe 
that there is a greater resistance to cross-fertilization between sub-races than between varieties of the 
same sub-race. There seems also a tendency for each type to maintain its own position, even when 
grown with other types, and there seems to be occasionally a transfer of one sub-type kernel to an- 
other sub-type of ear. There are exceptions, however, occasionally to be noted, but not of fre- 
quent occurrence, where intermediate characters appear, to the ear and its kernel. 

POD OR HUSK CORN. 

The Pod or Husk corn is a variety wherein each kernel is enclosed in a husk, as well as the ear. 
We have in our collection two races, the one a flint; the other a dent. The flint can be placed in sub- 
race A of our classification. Our dent ears belong, apparently, to the two sub-races B and C of our 
classification. It thus seems probable that this pod corn should not be classed as a separate race, 
unless it be solely for convenience. We present illustrations of the kernel type : Fig. 21. 




Of the flint type we have but one ear. This is lO-rowed, nearly cylindrical, shortish, rather 
small stalked, the husk abundant. 

Of the dent race, sub-race B, but one ear. This tapering, longish. lO-rowed, the stalk a little 
large, the kernels rounding over the butt. The kernel apparently polygonal, that is, if compressed in 
an unpodded ear, would have a sulcus between the rows. 

Of sub-race C, we grew many samples from seed exposed last year to hybridization from several 
varieties of sweets. Last year's crop yielded podded ears and unpodded ears. So far as examined 
the podded kernels were all a yellow dent ; the unpodded ears all yellow dent or yellow dent and sweet, 
or red dent and red sweet intermingled. This year's seed was a selection of podded kernels, unpodded 
dent, and sweet kernels, and was grown subject to hybridization from all the other races, but yet on 
account of the lateness of the silking, pollen from many of the earlier varieties was excluded. Of this 
year's crop some ears were fastigiate, as was also the case last year ; others heavily podded ; others 
lightly podded. The kernels of all of the 86 ears, so far as examined, were of a yellow or deep-red col- 
ored dent. The unpodded ears of this year's crop, T22 in number, vary from 12 to 24 rows, as fol- 
lows : — 8 were 12-rowed, ig were 14-rowed, 23 were i6-rowed, 34 were i8-rowed, 30 were 20-rowed, 
7 were 22-rowed, and i was 24-rowed. The red dent seed planted yielded 14 red dent ears, and 5 
white and yellow dent cars. From the unpodded seed, 132 plants yielded 10 podded and 93 unpodded 
ears ; from the podded seed, 166 plants yielded 76 podded and 29 unpodded ears. The sweet corn 
from unpodded ears yielded some sweet ears, but mostly sweet mixed with dent. 

The effect of current hybridization was observed on the unpodded ears in color, some kernels being 
red, red blotched and pink. As all the evidence in the preceding study is in favor of the view that 
change of kernel is produced by current hybridization, we may fairly assume that all the ears contain- 
ing sweet kernels were sweet ears, and that their dent kernels were formed by the prevalent pollen ; yet 




the fact that the crop from the sweet kernels showed a greater proportion of sweet kernels than did the 
seed used, with one exception, may cause our conclusion to seem at first view rather doubtful. On 
the other hand, the large number of ears without sweet kernels seems to strengthen it. Again, 
where sweet kernels were planted together, sweet pollen would be most likely to fertilize sweet ears, 
and this seems probably to have been the case. The podded kernels, so far as examined, show no 
effect from current hybridization, but as we did not care to destroy our crop, all the ears were not 
thoroughly examined. The podded ears are all distinctly cone-formed, and the same tendency plainly 
shows in the taper which exists on all the unpodded ears. The kernels are all wedge-shaped, no 
sulcus existing between the rows ; where sweet kernels are found, thev are all of sub-race C type. 

It is worth while to mention that stalks bearing the unpodded ears have an ordi- 
nary tassel. On the other hand, those stalks which bear podded ears have a very 
heavy, bunchy tassel, with very frequently more or less podded kernels interspersed. * itinu^aiAT 

When it is remembered that the most of our corn-seed is hybridized more or less /"'it;: 22. 
within its races, the uniformity in type which prevails is surprising. Thus, although our rice pop 
corn produces some cylindrical ears, I have known whole crops from other seed to be cone-shaped, 
and likewise have seen quantities of pearl pop without a single ear other than slightly tapering. 
While Canada corn as grown in Massachusetts furnishes many ears which are tapering and open at 
the butt, yet Waushakum corn, which has been bred pure, gives about all its crop with cylindrical 
ears, exceptions being apparently sports. 

SPECIES, NOT RACES. 

I have preferred calling the various distinct types of maize races until after the presentation of 
evidence. I am now inclined to consider the difference in the most cases as specific. We do not 
know the wild form of maize, nor is there sufficient evidence of a common origin to any proposed 
species. They came to us as they were at their discovery, and have remained distinct. Sachs defines 
species as "the aggregate of all the individual plants which have the same constant characters, these 
characters being different from those of other somewhat similar forms." Thome says a species 
is " onlv an assemblage of forms which resemble one another for the time being." Gray says the 
species is " the type or original of such sort of plant or animal thus represented in time by a peren- 
nial succession of like individuals," and "we refer to the same species those individuals which are as 
much alike as those are which we know to have sprung from the same stock." According to these 
definitions we must believe that we have species of maize, for as far as our knowledge extends each 
of our proposed species fulfills the requirements. It is, however, unsafe to confine our views to one 
distinction alone, for the totality of the plant, and not the seed only, should be considered, and I am 
not as yet prepared to point out differences in the plants of the various races or varieties. For the 
purpose of an Agricultural Botany we require agricultural species, as the separation of distinct forms 
furthers study and progress, and we may legitimately use the frame work of botany and employ a 
svmbol which shall indicate agricultural relations and which shall leave botanical relations undecided. 
I propose a- star between the generic and specific name, and would group what some 
prefer to call races, but which I prefer to call species, as follows : 

1. Zea * everta, the Pop-corns. 

2. Zea * indurata, the Flint-corns. 

3. Zea * indentata, the Dent-corns. 

4. Zea * amylacea, the soft-corns. 

5. Zea * saccharata, the Sweet-corns. 

6. Zea * induiata, var. vaginata, the pod-corns, flint type. 

7. Zea * indentata, var. vaginata, the pod-corns, dent type. 

I am indebted to a suggestion from Professor Asa Gray for the name of the 3d and 4th species, 
yet I would not by giving this credit have it assumed that my views meet his endorsement, or even 
approval. 



*Since writing the above, I have received three ears of pod corn. One of these ears is cylindrical, lo-rowed, and 
can be classed with sub-race A, Intermediate race type, Two of the ears are lo-rowed, slightly tapering, and can be 
classed with sub-race B, of the dent type. I append a figure of a kernel of the race provisionally called Intermediate, 
Fig. 22. 



So distinct, however, are these starred species, that the omission of the star would create no 
confusion even in systematic botany. It is diiificult to beHeve that the sub-races I have figured and 
described are not also to receive an agricultural classification, when sufficient material for study has 
been collected, but at present they can remain as varieties a, b and c of their respective starred 
species. My purpose is to assist in creating an agricultural botany which shall be of service for the 
study of economic relations, and whether I class the species or fixed forms under the head of agri- 
cultural species or of species seems of little consequence, except that the systematic botanist can use 
my evidence and remove the * in such cases as seems to him to be advisable. 



Parallelism of Structure of Maize and Sorghum 

Kernels. 



A Paper read before Section F., Minneapolis Meeting of the A. A. A. S., iSSj, by E. Lewis 

Sturfevanf, M. D., Geneva, N. Y. 



If kernels of flint, pop, sweet and Tuscarora maize be split parallel to the germ, each race will be 
see.i to present a definite arrangement of stmcture. Thus, the flint corn exhibits a germ surrounded 
by starchy matter and this in turn by a corneous envelope. In the pop-corn proper the germ is inclosed 
in the corneous matter, the starchy matter being absent except as the pop variety entrenches upon the 
flints. The sweet corn has a similar structure to the pop, but the corneous matter is translucent and 
wrinkled. In the dents the corneous matter occupies the sides, the starchy matter extending to the 
summit and including the germ. In the Tuscaroras the corneous matter is entirely absent, and only 
the germ and the starchy matter are to be made out. 

If kernels of sorghum be split in like manner, a similar arrangement is to be found. Thus, the 
seed of the varieties distributed under the name of " Dhourra," "African Wheat," and " Millo 
Maize," correspond to the flint-corn type, the germ surrounded by starchy matter, and this in turn 
included in a corneous envelope. In " Rice Wheat" we find the pop-corn type, germ and corneous 
matter, no starchy portion being visible. In " Neeazana " we have a structure modeled upon the dent 
corns, and in " Chinese .Sugar Cane " a structure modeled after the Tuscaroras, a starchy matter and 
germ without visible corneous matter. 

On account of the confusion of names it seems unnecessary to introduce further examples, 
although an examination of some thirty or forty so-called varieties show that this observation is founded 
upon general characters. 

In the case of the maize kernel we might assume that these differences have been produced by 
conscious selection, the kernel being the portion used, and the various races being fitted for uses 
founded upon the structure. In the case of the sorghum, however, this supposition would scarcely 
answer, as the kernel is of small size, and apparently has not been subjected to conscious selection. In 
view of this parallelism of structure, together with the probability that a like selection has not been 
exercised upon both, it seems safe to infer that these structural differences within each genus, have 
more meaning than simple variety differences, and that the same causes have been at work, inde- 
pendently of man's conscious selection, to produce the forms of kernel-structure which in Zea and 
Sorghum have such well marked and allied characteristics. 



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